Long before the days of antibiotics, Bacillus subtilis was used as a powerful probiotic treatment for many digestive symptoms, including traveler’s diarrhea and acute diarrhea in children. By the mid-1900’s, cheap antibiotics began to replace this probiotic in the US markets in the interest of cutting healthcare costs. However, the rest of the world continues to use Bacillus subtilis for a variety of GI symptoms.